Geology of Durness

This fault truncates the Durness Group carbonates and marks the boundary between these and the older Moine Psammites to the north. It trends E-W across the Faraid headland and into Balnakeil Bay, a few hundred metres north of Balnakeil House (marked by a small stream / gully at southern end of beach). A cliff face forming the southern limit to a small beach at Creag Thairbhe marks the only exposure of this fault plane and a large dune feature running up its side allows access to the well developed fault breccia (or cataclasites) found along it.

These breccias are very similar to those found at nearby Sango Bay, the main difference being that small clasts of psammite are also found within the calcite rich deposits. This shows that fault movements between the psammites and carbonates dislodged sections of these rocks through 'grinding' and later calcite cements now hold these in place. Reddening has also taken place due to hot fluids that would have once moved along these fault planes, depositing a red mineral known as hematite. At the base of the cliff along the beach, folded carbonates may also be found where these have been affected by the faulting.